Bioreactors are typically containers used to hold organisms for the purpose of harnessing their natural biochemical processes and are used for many purposes. Microbial reactors, which hold microorganisms, such as microalgae, bacteria, yeasts, and the like, are used to produce various products, including, but not limited to, foods, feeds, nutritional products, energy supplies, such as biodiesel, hydrogen, and alcohols, pharmaceuticals, and specialty chemicals. They also are used extensively for environmental control and remediation and waste treatment of many types.
Several types of large-scale bioreactors currently are in use. In a batch bioreactor, all of the stock materials, reactants, nutrients, and the like, are added at once to a controlled environment and the biochemical reactions are allowed to proceed. In a continuous flow bioreactor, materials constantly flow through the bioreactor. In either case, bioreactors may be enclosed, open or a combination of the two. In most cases, it is recognized that the performance of these reactors can be improved to produce more product or more efficient remediation or waste treatment.